1. Field of the Invention
The present invention relates to a straddle-type rough-road running vehicle, more particularly, in which an assembling performance of a vehicle body is improved.
2. Related Art
A straddle-type rough-road running vehicle or an automatic motorcycle is mounted with an engine unit which is formed by integrally combining a belt-type stepless transmission (change gear) with an engine body. In order to prevent an adverse influence of heat, generated by an operation of the transmission, on a V-shaped belt or seal members of the transmission, the engine unit is provided with a belt-cooling device.
The belt-cooling device has a function of introducing a fresh air as a cooling wind through an intake port and a duct from an external portion into a portion, for example, i.e., a belt case in which the transmission is accommodated. Parts and members in the belt case are cooled by the cooling wind. Thereafter, the cooling wind is transferred through, for example, another duct and then discharged from an outlet port to the atmosphere.
Further, since it is not preferable for the flowing air introduced into the belt case to contain any moisture (water) content, a liquid/gas separating member having a box-shape is provided to an air intake duct at the most upstream side thereof.
Such conventional straddle-type rough-road running vehicles are disclosed in, for example, the following three patent documents: Japanese Patent No. 2843570; Japanese Patent Laid-open (KOKAI) Publication No. 2000-313385; and Japanese Patent Laid-open (KOKAI) Publication No. 2005-315214.
However, the intake port and the outlet port provided to the belt case are usually arranged to a central portion of the vehicle body frame in a longitudinal direction or an outside portion in the width direction of the vehicle body frame, so that it has been obliged to layout an intake duct and an outlet duct so as to be connected to the intake port and the outlet port in a very complicated manner, thus involving inconvenient working or labor and deteriorating an assembling performance of the vehicle body.